cmd/compile: repair display of values & blocks in prog column

This restores the printing of vXX and bYY in the left-hand
edge of the last column of ssa.html, where the generated
progs appear.

Change-Id: I81ab9b2fa5ae28e6e5de1b77665cfbed8d14e000
Reviewed-on: https://go-review.googlesource.com/c/141277
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Yury Smolsky <yury@smolsky.by>

src/cmd/compile/internal/gc/ssa.go

@@ -147,6 +147,7 @@ func buildssa(fn *Node, worker int) *ssa.Func {
 	s.f.Cache.Reset()
 	s.f.DebugTest = s.f.DebugHashMatch("GOSSAHASH", name)
 	s.f.Name = name
+	s.f.PrintOrHtmlSSA = printssa
 	if fn.Func.Pragma&Nosplit != 0 {
 		s.f.NoSplit = true
 	}
@@ -5000,9 +5001,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 	var progToValue map[*obj.Prog]*ssa.Value
 	var progToBlock map[*obj.Prog]*ssa.Block
 	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
-	var logProgs = e.log
-	if f.HTMLWriter != nil {
-		// logProgs can be false, meaning that we do not dump to the Stdout.
+	if f.PrintOrHtmlSSA {
 		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
 		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
 		f.Logf("genssa %s\n", f.Name)
@@ -5085,7 +5084,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 				valueToProgAfter[v.ID] = s.pp.next
 			}
 
-			if logProgs {
+			if f.PrintOrHtmlSSA {
 				for ; x != s.pp.next; x = x.Link {
 					progToValue[x] = v
 				}
@@ -5103,7 +5102,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 		x := s.pp.next
 		s.SetPos(b.Pos)
 		thearch.SSAGenBlock(&s, b, next)
-		if logProgs {
+		if f.PrintOrHtmlSSA {
 			for ; x != s.pp.next; x = x.Link {
 				progToBlock[x] = b
 			}
@@ -5136,7 +5135,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 		}
 	}
 
-	if logProgs {
+	if e.log { // spew to stdout
 		filename := ""
 		for p := pp.Text; p != nil; p = p.Link {
 			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
@@ -5155,7 +5154,7 @@ func genssa(f *ssa.Func, pp *Progs) {
 			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
 		}
 	}
-	if f.HTMLWriter != nil {
+	if f.HTMLWriter != nil { // spew to ssa.html
 		var buf bytes.Buffer
 		buf.WriteString("<code>")
 		buf.WriteString("<dl class=\"ssa-gen\">")

src/cmd/compile/internal/ssa/debug.go

@@ -153,8 +153,12 @@ var BlockEnd = &Value{
 // RegisterSet is a bitmap of registers, indexed by Register.num.
 type RegisterSet uint64
 
+// logf prints debug-specific logging to stdout (always stdout) if the current
+// function is tagged by GOSSAFUNC (for ssa output directed either to stdout or html).
 func (s *debugState) logf(msg string, args ...interface{}) {
-	s.f.Logf(msg, args...)
+	if s.f.PrintOrHtmlSSA {
+		fmt.Printf(msg, args...)
+	}
 }
 
 type debugState struct {

src/cmd/compile/internal/ssa/func.go

@@ -37,9 +37,10 @@ type Func struct {
 
 	// Given an environment variable used for debug hash match,
 	// what file (if any) receives the yes/no logging?
-	logfiles   map[string]writeSyncer
-	HTMLWriter *HTMLWriter // html writer, for debugging
-	DebugTest  bool        // default true unless $GOSSAHASH != ""; as a debugging aid, make new code conditional on this and use GOSSAHASH to binary search for failing cases
+	logfiles       map[string]writeSyncer
+	HTMLWriter     *HTMLWriter // html writer, for debugging
+	DebugTest      bool        // default true unless $GOSSAHASH != ""; as a debugging aid, make new code conditional on this and use GOSSAHASH to binary search for failing cases
+	PrintOrHtmlSSA bool        // true if GOSSAFUNC matches, true even if fe.Log() (spew phase results to stdout) is false.
 
 	scheduled bool // Values in Blocks are in final order
 	NoSplit   bool // true if function is marked as nosplit.  Used by schedule check pass.